The system works by creating a low-power static electric field around the vehicle. When the field is disrupted beyond set parameters, the system dumps the contents of a high-capacity accumulator or capacitor into the field, in hopes of disrupting or destroying the incoming object.

The electric field has no effect upon Laser Weapons or PAWs. It has limited effect upon larger kinetic penetrators. It does work very well against the plasma stream generated by a HEAP warhead and reasonably well against the discharge of High-Energy Weapons.

The most severe limitation of the ESA system is the accumulator bank (or banks) required to power the field. The protective phase of the electrical pulse lasts a few microseconds, enough to disrupt a single attack or a series of closely timed ones. Most ESA systems contain several accumulator banks designed to hold off between four and a dozen attacks, but the system depends upon the external power to recharge the banks to provide continual protection.

Engaging the electrical pulse also produces a large and distinct radio pulse. For most designers, this is not a severe limitation as the engagement of the electrical field indicates the target has already been spotted and engaged.